Storing/referencing users

Is it best practise to:

1. Store users in a User table, with a numeric UserID as primary key, and reference these users in other tables using that UserID as a foreign key? Also, this would require an additional username field.

or

2) Store users in a User table, with a text Username as primary key, and reference these users in other tables using the Username as a foreign key?

TIA. Received on Sat Jun 03 2006 - 08:33:09 CDT